The present invention relates to a composite profile, in particular a heat-insulating composite profile, for windows, doors, facades or skylights. The invention also relates to a method for producing such a composite profile.
Prior art profiles, such as the profile disclosed in DE 25 52 700 and shown in FIG. 1, consist of a first and a second metal profile and two mutually parallel insulating profiles which connect the metal profiles with each other. The insulating projections are preventing from coming out of the receiving grooves by base sections which are disposed in the insulating profiles and engage with the receiving grooves of the metal profiles, as well as a tight press fit of the insulating projections in the receiving grooves. The press fit is implemented by forming or pressing the outer or inner projections onto the insulating projections at the time the insulating sections are inserted into the receiving grooves.
The composite profile is produced by first orienting the metal profiles relative to each other so that the receiving grooves for the insulating profile face each other. The insulating profiles are then pushed or inserted into the receiving grooves and later aligned with each other in a mounting device and tensioned, with the tensioning forces applied to the outside surfaces. The composite is fixed by plastically forming projections on the insulating profile.
The projections can be formed in the mounting device by either moving the profile past the device or by guiding the device across the stationary profile for forming the projections.
The construction depth of the composite profile of this type is calculated by adding the construction depths of the sequentially arranged individual elements, first metal profile, insulating profile and second metal profile. Conventional profiles have therefore a construction depth with a manufacturing tolerance which is the sum of the manufacturing tolerances of the individual elements. Details of the tolerance budget of the profile of FIG. 1 are given below.
The tolerances of the metal and plastic profiles cannot be reduced below certain minimum tolerances governed by manufacturing conditions—typically, relatively complex technical processes, such as extrusion molding of the metal profiles and extrusion of the plastic profiles (insulating profile), are selected—, which already causes a significant increase in the manufacturing cost of the profiles. Accordingly, relatively large variations results when the tolerances of the individual components are added which in practice can amount to a total tolerance g=±0.7 mm. The alignment tolerances mentioned above have also to be added; these are, however, typically rather small and may even approach zero.
The heat-insulating composite profiles for windows, doors and facades are assembled into frames or crossbar/post constructions, wherein the profiles are mitered or butt-joined. The large tolerances of the various assembled profiles cause different problems. For example, large tolerances can result in an irregular visual appearance. The tolerances can also produce sharp edges where the profiles intersect, which can cause injury during operation or cleaning. In addition to these effects, the tolerances also create technical problems when the profiles are joined or mechanically finished, for example, during sawing or milling for installing fittings and accessories, and lead to poor functionality of the completed elements (for example, leaks, binding, etc.).
It would therefore be desirable and advantageous to obviate prior art shortcomings and to reduce the total tolerance of the composite profile and to relax limitations in the tolerances of the individual profiles.